Preflight reflex and gunnery trainer



April 13,1943. c, OCKER 2,316,181 Q PRE-FLIGHT REFLEX'AND,GUNNERY TRAINER Filed Sept. l0,' 1941 4 Sheets-Sheet l April 1943- w. c. OCKER ETAL, 2,316,181

' FEE-FLIGHT REFLEX AND GUNNERY TRAINER Filed Sept. 10, 1941 4 Sheets-Sheet 2 roRA/E April 1943- w. C. ocKER ET AL 2,316,181

7 PRE-FLIGHT REFLEX AND GUNNERY TRAINER Filed sept. 10, 1941 ,4 Sheets-Sheet 3 reg/w y:

4 Sheets-Sheet 4 Filed Sept. 10, "1941 Patented Ap -1s, 1943 e f mines: o ens A i .wmaaeomgsamamwm i t BarksdaleFieli Ll- 1 Application September 10, museu mumv 1901mm. (01. 35-12 o a (Granted onscrare m or March 3, m3, 5,

, o o amended April so, 1928; see 0.9. 157) The invention described herein maybe manufactured and used by or for Government for governmental purposes; without the payment to us of any royaltythereonr i This invention 'relatesto ground training of flying an airplane and is designed to'condition the physiological and psychological reflexes of the student to such an eiltent thatthe dual instruction time in an actual airplane may be considerably lessened; thus conserving thevaluable time o of a flight instructor. 1

l fThe learning'of thecoordinating'movement of the controls of an airplane to specially orientate the same is acquiredbyconditioning the' physiological reflexes of the student by constant repetitionof the controls until the action becomes automatic. This conditioning of the reflexes student has no aptitude for iiyingafter considerable instruction time has been expended. The

pa paratusfor givingprimary instructionin the art consumes much valuable instructor's time when w carried outin' the usual dual place training air- "plane and often results in discovering thatthe second stage of 'leaming to fly asnotedsiseoncemed with the centroid! the aircraft to traverse a desired course and requires the trainingof the psychological reilexes such as theevaluationsof situations and requiredjactions to be taken when a given situation presents itself niches in the event some obstacleis encountered without forewarningand in which physiological and psychological reactions will be involved.

So far as we are aware there is in use no ground vehicle or trainer which is capable of use in training the prospectiveflyingstudent inboth the spacial orientation of an aircraft and directional control of the "same to avoid obstacles, to thereby give the necessary conditioning ofthe physiological and psychological reflexes as outlined above, in the manner as accomplished by the present invention. p

In accordance with the present invention there I is provided an aviation ground trainer comprising a power propelled vehicle having supporting wheels, the rear wheel or wheels thereof being steerable bythe student through themedium or rudder pedals or thewlike, and having a subi'rame forming a eockpit inclosure with a seat for thestudentand including! set of controls i duplicating the usual rudder and stick or wheel type controls employed in an airplane. The subframe is mounted in bearings for tilting about the longitudinal axis of-the vehicle and actuated by power means controlled by the stick or wheel control so as to cause thesub-i'rame to tilt to The trainer is simulate thebanhing or an airplane under the action of the ailerons. The sub-frame is also provided with a nose or cowl section which is movable up andi downbyfpowergmeans under the control of: the'xfore and aft movements of the control stick or its equivalent to simulatethe .nosing'up or down. of an;airplane. The design of the power actuated means for respectively causing the lateral tilting of the sub-frame and- ;the vertical shifting of. the nose or cowl section is .such, that a givenilateral or fore and aft motion of the control column respectively. W1 1 cause aproportionate tilting of the sub-frame or shifting of the cowl section respectively, at a rate proportional to the movement of the control column, and the return of the controloolumn to the neutral position will leave thesub-frame tilted to simulate bank, or leave the cowl section in a position to represent ainosing,

up or down of an airplanerand in order to the sub-frame and shiftable cowl section normal 'levelspositionpopposite ,control movements must be applied bythestudent exactly in restoring an airplane to the '-level; flight pos on.

banking of the cockpit enclosure for theparticular rate of turn of the trainer-1nd also to warn of the approach of the shiftable cowl section to an angle-corresponding tothe stalled position v of an aircraft. The stall warning systern'is also connected to a pair of solenoid controlled dashpots connected to thecontrol column torender the dashpots inoperative to impose any resistance to the operation of the control column and thus simulates the feeling of. lack of control response which accompanies a stall. i a i o I In order to simulate the air loads imposed on an aircraft control column due to change in throttle setting and the neutralizing of such loads by adjustment oi' the trimming sear resilient means are provided operable with the engine throttle control to imposes. load which is felt on the control column. and other means resembling the stabilizer adjustment gear of'an airplane are provided for. neutralising such loads.

A. ground trainer-in accordance with the invention also serves as anexcellent mediumin giving preliminary training in gunnery such'as theoperation oi nxed'type airerait machine guns. This is accomplished by mounting a .22 caliber atomatic rifle, which may be a standard commercial gun modified to give full automatic action, on the-movable cowl or nose section of the o provided'with signal which indicate by aural signals the improper cockpit inclosure and providing a wire pull type of control extending from the gun to the control column and terminating in a trigger which may be depressed to actuate the trigger mechanism on the gun to cause the same to be fired. A tortuous course to be steered may be laid out on the firing range by means of stakes or the like and suitable targets placed 'at different elevations with respect to the level line of sight from the trainer, the targets being so arranged that the student will have a direct aim thereon only for a brief period of-time, thus in effect simulating the firing at an enemy aircraft. The low caliber practice type of machine gun may be employed 1 in place of the automatic rifle and the latter term is intended to embrace'both types of arms. It is therefore the principal object of the invention to provide an aviation ground trainer for teaching a student the art of controlling an aircraft, comprising a power propelled wheeled vehicle adapted to be steerably controlled by the student occupant in a manner similar to the directional control of an aircraft and so arrange? as to simulate the banking and nosing up down flight attitudes of an aircraft under the control of the student, whereby the physiological and to some degree the psychological reactions of the student are conditioned prior to actual flight instruction.

It is another object of the invention to provide anaviation ground trainer comprising a power propelled steerable wheeledvehicle having means forming a cockpit inclosure for the student receiving instruction, and the cockpit being laterally tiltably mounted thereon, said cockpit iiiclosure being provided with means shiftable in a plane normal to the tilting movement thereof to simulate the nosing up or down of an airplane during flight, controls being mounted within said cockpit inclosure duplicating the controls of an airplane, the said controls being operative upon actuation by the student to respectively steer the vehicle, cause a lateral tilting of the cockpit, or cause an upward or downward-displacement of said shiftable means.

Another object of the invention is the provision in aviation ground training apparatus of the character described, of aural signalling means for signalling the improper use of the controls,

the control column further being provided with yielding resistance means normally opposing movement of the control means and the signalling system being operative to render the resistance means ineffective to thereby simulate loss of control when the trainer simulates the stalled flight condition of an airplane.

It is another object of the invention to provide in aviation ground training apparatus of the type comprising a power propelled steerable wheeled vehicle, said vehicle having means for simulating remote from the trainer and means associated with the control means for controlling the firing of the rifle or machine gun.

Other objects of the invention not specifically enumerated above will become apparent by reference to the detailed description in the specification and to the appended drawings in which: Fig. 1 is a perspective view illustrating the general assembly of the principal component parts of the invention, and;

Fig. 2 is a top perspective view illustrating de tails of the vehicle drive and power take-off mechanism, and;

Fig. 3 is a perspective view illustrating details of the trainer disclosed in Fig. 1, including the lateral and directional control system, and;

Fig. 4 is a view partly in section illustrating the construction of a solenoid controlled dashpot employed in the trainer control system, and;

Fig. 5 is a schematic view illustrating the details of the control system for causing simulated changes in elevation and also schematically illus-- trating the simulated trim tab or stabilizer adjustment, and;

Fig. 6 is a diagrammatic illustrationof the signal system employed in conjunction with the trainer control, and;

Fig. 7 is a fragmentary perspective view of an automatic rifieor low caliber machine gun as employed on the trainer for gunnery practice.

Referring noW to Fig. 1, the reference numeral 10 generally indicates the main frame of the trainer, which is trapezoidal in plan form, and

comprises two identical spaced side frames ll made of seamless steel tubing, or the like, united by welding, the side frames ll being spaced by means of front transverse frame members I2 and rear transverse frame members I3. The front portion of theside frames Il taper inward and terminate in wheel fork fittings M, which serve to rotatably journal a rubber tired vehicle wheel l5, the wheel l5 being non-steerable and serving as a drive wheel to propel the trainer over the ground. A mounting base, I! is provided immediately over the front wheel l5 and is suitably supported by tubular bracing members fromthe frames II and serves as a mounting for a conventional type single cylinder internal combustion engine l8, which is preferably of the 4-cycle type controlled by a manually regulated throttle valve (not shown). The engine I8 is adapted to transmit its power through a mercury, or other type of speed responsive coupling l9, such that the full motor torque is not delivered to the driving side of the coupling, until the engine speed exceeds a predetermined amount, couplings of this character being'well known in the art and commercially available. The drive shaft of the coupling I9 is providedwith a driving pulley 20, which through the medium of a V-belt 2| is adapted to drive a similar pulley 22 mounted on the outer end of a countershaft 23 suitably supported in bearings (not 'shown) carried by the main frame l0. As seen in Fig. 2, the countershaft 23 is also provided with a pulley 24 which by means of a V-belt 25 is adapted to drive a large pulley 26 (Fig. l) rigidly secured to the hub of the driving wheel I5. and i rotatable therewith, the pulley 26 serving to transmit the drive from the engine I8 to propel the trainer.

As seen in Fig. 2, the countershaft 23 is also provided with a pulley 21 which, by means of a V-belt 2B, is adapted to drive a pulley 29 mounted on the jackshaft 30, the latter being suitably supported in bearings (not shown) mounted on the trainer frame If). At its outer end the jackshaft 30 is provided with a friction disc 32 which serves as a power take-off means for utilizing a portion of the power output of the engine Hi to energize servo mechanism as will be hereinafter described.

a friction roller 33 which is slidably keyed on a shaft 34 to drive thefsame, the shaft 34 being provided at its outer end with a worm .35. The

33 which is slidably mounted on a guide member I I 2,310,181 The friction disc 32 is adapted to co-operate with 33 and adapted to shift thefl'iotion roller 33 radifallyin. either directionfrom the center of the friction disc 32, thus causingthe roller and the shaft 34 to be driven in either of two directions at a speed proportional tothe radial distance of the friction roller 33 from the center of thefriction disc 32. The hiftingfork 33 has connected therewith, on one side acontrol cable .40 adapted to. shift theforkfflpand roller 33 axially along side ofthe shiftingfork 3 3, isioperative toqause a shifting of the friction roller radially with respect to the friction disc 32 inthe oppositedirection,-,the control cables, 40 and 4| passing over suitable guidespulleys 42 and 43 respectively and adapted to :be connected to a stick control mechanism, hereinafter more fully described.

1 As seen in Figs. 2 and 3, the previously mentioned worm 35 moimtedzon theshaft- 34 and driven by the friction roller 33 meshes with a worm wheel 36 so as to rotate the same in either directionin accordance with the direction of rotation of the shaft 34,:the gear 36 being adapted to drive a cable drum 31, integrally connected thereto, the cabledrum 31 serving in the lateral control system of the trainer in a manner later described. a i

Referring to Figsal and 3, the side frames ll forming the main frame III are each provided at wheel forks 50 are interconnected by means of a pivoted radius bar and adapted to be jointly ,theshaft 34 to the left, as seen in Fig. 2, ands. 3 similar control cable 4 I, connected to the opposite guide members 65 which are similarly mounted on each side of, the cockpit inclosure and serveas guides, or tracks, for wheeled carriages 65.1, each of which is rigidly secured to, a shiftable cowling or front deck portion of the cockpit inclosure, the top of the shiftable cowling section 66 serving as a reference line with rmpect to the visible horizonto simulate the nosing up or nosing downof an actual airplane relative to the horizon. The center of curvature of the arcuate guide members 65 is so selected and arranged that it coincides with a transverse-axis passing through the eyes of thestu'dent occupant of the trainer, to thus cause a shifting of the movable cowling section 66 in la mannerto give a true simulation of the change in attitude of the nose and front cowling of an airplane as the same is caused to move relative to the .visible horizon by actuation of theairplane rotated about their pivotal axes by means of forces transmitted through a steering link 54 pivotally connected at one end to thradius' rod 53 and at its other endto be suitably pivotally connected to asteering arm 55, the latter being rigidly secured to and rotatable witha pulley 56 suitably mounted on the frame l0 bymeans (not shown) for rotation about1 an axis parallel with the pivotal axes of the wheel forks Ill. The pulley 56 is adapted to beangularly rotated about its pivotal axis by means of acable 51 which is securely clamped at one point to the pulley I8 by means of a well-known typeofcable clamp, indi-. catedatiiB. M a

1 Again referring to Figs. 1 and3, the reference numeral 60 generally indicates a sub-frame or platform constructedof welded steel tubing and 1 provided with aiioor 6i and a seat 62 for the student occupant of the trainer. The sub-frame 60 is adapted to be suitably covered byremovable sections of artificial; leather, or the like, (not shown) .to provide a cockpitinclosure simulating the cockpit of a conventional airplane. The subframe 30, hereinafter also referred to as the cockpit inclosure, is provided with longitudinally extending hollow pivots which are adapted to be journaled in suitable bearings 64 (Fig. 3) mounted on the transverse frame members I! and 13 respectively to support the cockpit inclosure for lateraltilting movement in either direction relative to the longitudinal axis of the trainer main a frame in. :As seen in Fig. 1, the cockpit inclosure, or sub-frame 60, isprovided with pairs of arcuate longitudinal control. The weight of the shiftable 'cowling section 36 and wheeled carriage 55" counterbalanced by suitable weights carried within the tubular guides 61 and connected'to the shiftable cowling section 36 by means of cables 63, or the like. The terminal ends of acable 39 are secured to the shiftable bowling section 66 at spaced points and the cable 69 is led over suitable guide pulleys 10, secured toythe sub-frame i0, and the mid portion of the cablei's secured to a traveling nut or carriage ll mountedqon and adapted to be shifted by a lead screw12, also supported bythe'sub-f rame 60. The lead screw" 'is adapted to be driven in the forward or reverse thereof connected in series with the split field coils of the motor 13 to cause the same to 'run in a desired direction and at a speed dependent upon the position of a contact arm 13, which is rotated by means of the trainer controlsystem,

as will'be hereinafter described. The motor I3 in driving the lead screw 12 causes a feeding motion of the nut 'II in either direction from the middle position and thereby causes the cable '33 to elevate ordepress the shiftable cowling section- 66 from a neutral'or level position. i

Directional control system Referri'ngto Fig. 3, the floor ll of the cockpit inclosure GIIisseen to have pivotally mounted thereon a 'pair of rudder pedals lll which are adapted to be actuated by the feet of thestudent in the same manner as the conventional rudder pedals in an airplane. The rudder pedals are respectivelyconnected to the terminal ended the cable 51 which,passing over suitable guide pulleys, projects through the rear hollow pivot bearing 83 of-the cockpit inclosure and passes around the pulley 58 as previously described, the

cable being secured to the pulley, as noted. by the cable clamp 53. Bydepressing-either of the rudder pedals 80 the pulley Ii -is rotated about its axisycausing the steering arm 55 to shift the steering link and through the radius rod I3 toca'use a rotation of the castered wheel forks 50 about their'pivotal axis either to the right or the left, asthe case might be, the depressionsof the left rudder pedal causing a turning of thevehicle to the left, andysimilarly, a depression of the right rudder pedal causing a turning of the vehicle in the corresponding direction. Suitable restraining means, such as shock cords connected to thecastered wheel forks 50, and not shown, are provided for preventing excessive turning orunstable action of the rear wheels of the trainer.

. free flow of fluid is permitted through the bore It is thus seen that by actuation of the rudder pedals 80 the student occupant of the trainer Irrit erol control Q "ugl ness-s controlling urrealism of the cockpiis inclosure to thereby simulate the banking of an airplaneun'der the action of ailer displaced laterally to cause rotation of the rockshaft 82'. Adouble armed lever 86 is mounted on the front end-of the rockshaftandfhasits armsrespectiv'ely -conniected" to the control" of cables Y may steer the same in a desired courseiii-exactly v the'same manner as an-airplane is directionally controlled in a plane parallel to the surfac of the -earth.i'- J lil 40 and which, as previously noted, are adapted to shift'thefriction roller 330i the power take on. mechanism .drivably associated with the. ,trainerapropulsion 'power plant l8. Cables 48 andllfare arranged to pass through the hollow front'pivotof the cockpit inclosureso thattilting I movement of thejsame will] not affect the con'trol.

I {also-connected to th'epi'ston rodof a, two-way oil 7 dashpot 81, which'isiillustrated-in detail in Fig. 4,

.and asther seen,;comprises a closed cylinder 88 adapted to befilled, with oil and having apiston 89 'slidably mounted therein, the piston being connected .to the piston rod which passes throughoneend of the cylinder 88 in sealing re- 'la'tion' theretor "I he'cylinder 88- has fluid passageways 9la and 31b communicating with opposite ends thereof respectively, the passageways being interconnected by means-of-aby-pass channel 8|, the

I flow-through which; in{',:,either"direction, is refstricted .by-:means of an -tadjustable needle valve l2;-. At their outer ends the passages 91a and Slb u-communi'catewith, aplugged bore 83 formed in a'fvalve casing'form'ing part of the cylinder 88.

' 'The-comm'unication-oi the passage 91a with the bore iscontrollediby a pressure balanced spool w type piston valve 38 having one of its head po.r-'

t ons normally in the position as shown in Figure 4 blocking the communication between the said passage 9m and the bore 93. An electrical solenoid 8i hasia spring loaded plunger 96 connected to the valve 84 and when the solenoid is energized the plunger pulls the valve axially .to'the leftfrom the position shown in Figure 41 When the valve 84 is in the position as shown in ,Figure 4 all flow of fluid from one side of piston '88 to the other must pass through the restricted passage 8i and the resistance then offered by the dashpot 81 resists the lateral motion of the later described.

"from either of the passages Ma and 9") to thereby cut out substantially all of the resistance of the dashpot to lateral motion of the control column, thus simulating the lack of feel of load on an airplane control column when approaching a stall. The solenoid is adapted to be actuated in conjunction with a signal system as will be Referring again to Fig. 3, the cockpit inclosure 60 is seen to be provided with an arcuate guide member 98 rigidly secured thereto and which is adapted'to be connected at its center point with an endless cable 99 which passes over guide pulleys I00 fixed to the trainer frame ill, the cable .99 also being wound around and secured at one point to the cable drum 31, previously described Lateral movement'of the control column ineither direction will cause a corresponding rotation of I the rocks haft 82 and double armed lever 86 which will cause either cable 40 or 4| to be tensioned to cause a shifting of the shift fork 38 and friction roller 33relative to the-friction disc 32 to cause as best illustrated in Fig. 2 a rotation .of the friction roller and shaft 34 in a given direction and at a velocity proportional to th magnitude of the shifting of the friction roller 33, which of the cable 99 in one or the other'direction and the motion of the cable will cause 2. corresponding tilting movement of the cockpit inclosure 50 through the means of the arcuate guide 98 secured thereto. If; after having deflected the control column in either direction laterally from its neutral position, the control column is rapidly returned to the neutral position, the friction roller 33 will be correspondingly rapidly shifted until it is centrally disposed with respect to the friction disc 32, at which time further driving of the friction roller 33 by the disc 32 will stop, thus leaving the cockpit inclosure Bil tilted in either direction about the longitudinal axis of the trainer in any desired amount between certain predetermined limits,'which may be determined by means of suitable stop members (not shown). This feature of the lateral control thus causes the control of the tilt of the cockpit inclosure 60 to exactly duplicate the conditions present when controlling the lateral inclination of an aircraft, for example when making a turn. Since the control stickin the airplane is moved laterally from the neutral position until a desired amount oflateral inclination or banking of the airplane has been secured, and the stick is,

then returned to the neutral position, leaving the airplane inclined with respect to the horizon and in order to return the aircraft to the level flight position it is necessary to apply opposite control,

.that is, move the control stick in the opposite direction until the aircraft is again level, when the stick is then returned to the neutral position, and

a similar control must be eifected in the present medium of the control stick, or the like. It is r 2,810,181" to be understood, however, that thelateral motion of the control column 85 may bereplacedby, the conventional wheel type control, it only being necessary in such a case that thefriction roller control cables 40 and 4] be alternatelytensioned to cause a displacement of the friction roller in oppositedirections as the-control wheel stood that in place of the friction drive servo mechanism employed to cause tilting of the cock- Longitudinal control In orderto simulatethe change in the attitude oi the longitudinal axis of an aircraft, or referred to above as the nosing up or downof an airplane, the shiftable cowl section 66 of the cockpit inclosure, positionally. controlled through the medium of the reversible electric servo motor I3 (as seenin Fig. 1) is employed, and in order to coni trol positioning of the shiftable cowl section, the

control column (as seen inFig. 5) has connected thereto a longitudinal extending push rod I05 universally pivoted at its outer end to; one arm I of a bell crank lever pivotally mounted for movement in a longitudinal plane, the other arm I I0! of which is pivotally connected to a rack I08 which reciprocates in a vertical plane and causes rotation of agear I-09which is adaptedto be secured to the shait for actuating the contactblade I. of therheostat I5, which as previously noted inthe description of Fig. 1, is adapted to control the reversible electric motor I3. As the control column 85 is moved in a fore andaft direction from a neutral position, the push rod I and bell crank arms I06 and I01 are operative through the rack I08 to cause a rotation of gear I09 and the contact arm I6 of the rheostat I5 toVcause I field conductors I30, or 132) through the respective resistances 11 or I0 causing the motor I3 to run ineither of two directions witha speed dependent upon the magnitude of the angular rotation of the rheostat blade I6 from its neutral or dead .posltion.

Again referring, to Fig. 5, itwill be seen that since the; angular position of therheostat contact blade, I8 is dependent upon the longitudinal deflection of the control'column 85 from its neutral position, the rate of elevation or depression of the shiitable cowl section 66 from its neutral position will be proportional to the fore or aft deflection of the control column similarto the I change in the longitudinal attitude of an aircraft 'in proportion to the change in theelevator set ting. If, after moving the control column 05 in either afore or aft direction, the controlcolumn is returnedtoth n utrai position, the shiftable cowl section 86 wii remain in eitheran elevated or depressed position dependent upon themagnitude of the control column deflection and the time during which such deflection was main I i srotated in a clockwise or counter-clockwise Y direction respectively. It is also to be under- ,tained, and in order to restore the shiftable cowl section to the neutral position an opposite movement cl the control column 05 must be made,

thus identically simulating the longitudinal'control of, an actual airplane by actuation of the control column. When the student sitting-in the trainer actuates the control column 85 in a fore or aft direction, the line of sight from the students eyes across the top of the shiftable cowl section 66 is altered with respectto the visible horizon in exactly the same manner as it the student when flying in, an aircraft, caused the nose of the aircraft to be elevated or depressed with reference to the horizon. In order to simulate the feel-of the air loads from anairplane elevatonthe control column 05 has connected therewith a second solenoid controlled dashpot II5, identical in construction with the dashpot a1 illustratedin Fig. 4, and previously described.

The dashpot H5 is normally operative to ofier a restraint to the fore and aft motion of the control column in proportion to the rate of movement thereof and is adapted to be rendered ineffective by the actuation of the, solenoid valve control thereof which co-operates with a signal system later described. I

Trim' tab or stabilizer control- I Since most aircraft are-provided'with means to adjust the trim of an aircraft, thatls, its balanced condition when the elevator control is released, and accomplished generally by adjustment of an adjustable stabilizer, or by shifting the position of a trimming tab mounted, for example, on the airplane elevators. it is desirable to simulate such a trimming control in a ground trainer and such a control, is also illustrated in Fig. 5, in which the control column 05 is seen as having connect.- ed therewith a pair of resilient elements, such as lengths of elastic shock cord I III and I I9, connected on opposite sides; of the control column at the inner ends thereof, each of the resilient elements H0 and H9 having their outer ends "connected to an endless cable I20, which after passing over guide pulleys is wound around and secured to a rotatable cable drum I2 I, the latter being actuated by means of a lever I22, simulat ing the trimming adjustment lever provided on an airplane. The lever I22 is adapted to be held in any adjusted position by means of a notched sector plate, or the like, I23, co-operating with a detent, or the like, provided on the lever I22.

As the lever I22 is moved in either direction from its neutral position the drum I2I will be correspondingly rotated to tension either of theresilient elements act I IS Ito impose a loading tone on the control column ,85 which simulates either a nose-heavy or tail-heavy force,such as is felton a control column in an aircraft when the sameis not in longitudinal balance,-and accordingly, by actuation of the lever I22, the student may apply forces to the control column to,

cause a balancing so that when the control column is in the neutral position no restraining force thereon is felt, this operation thus simulating the adjustment of the stabilizer or other trimming gear when flying an airplane, and in the case of the trainer the instructor maypositlon the lever I 22 so that forces are imposed upon the control column equivalent either to anose-heavy condition or tail-heavy condition, as. he desires, thereby forcing the student to set the trimming adjustment in the proper position in order to hell 'tralize any forces on thecontrol stick when the same is in the neutral position.

Since most air lanes are so designed such that when the throttle is closed to cut off the engine power,the airplane is slightly nose-heavy, so as to assume a proper gliding angle when the power is cut off. This condition is simulated in the present ground trainer by connecting the engine throttle control to the trim tab adjustin mechanism above described (illustrated in Fig. The cable I24 is secured at one end to the endlesscable I and at its other end-is secured to an engine throttle control lever I26, suitably pivotally mounted on a bracket in the cockpit inclosur 00. The cable I24 has inserted in series therewith a spring or other resilient means I125 so that the throttle control lever when moved in a closing direction will tension the spring I 25 and through the cable I24 will transmit a force to the cable I20, and the resilient element I118. so as to impose a force on the control column I! resembling the nose-heavy condition in an airplane; The throttle control lever I26, as shown, is provided with a double arm lever I21, which is adapted, by means of cables I28, to actuate the throttle of the engine I8 of Fig. 1, the throttle not being shown, since the same is well known in the art. As the throttle lever I28 is moved to the open position th cable I24 and spring I25 become slack sorthat no restraining forces are introduced from the throttle control onto the control column 85. r 7

Signal system eratlon forces, caused by the turning of the trainer. The inclinometer I30 comprises a pendulum Ill pivotally mounted at its upper end by means of a bearing I32, which is secured to the instrument board of the trainerso that the pendulum may rotate about an axisparallel tothe longitudinal axis of the trainer. The pendulum Ill is provided with an electrical contact I33 which may engage either of a pair of adjustable contacts I34 located on opposite sides thereof and having a predetermined clearance from the pendulum contact I23. The pendulum Contact I33 is electrically connected to the battery I50 through a grounded conductor I35 and the contacts I34 are connected by means of a'conductor I36 to the positive terminal of the battery I50,

the conductor I35 having a conventional electric signal, such, as a horn I40, connected i series therewith. The lateral motion of the pendulum I3I, due to acceleration forces arising from turning of the trainer, is opposed by a pair of dashpots I31 which have their piston rods pivotally connected to the pendulum and the damping influence of the dashpots I3'I- being controlled by adjustable needle control valves I38. The signal control system thus far described is so operative that if the student fails to cause a tilt or simulated bank of the cockpit inclosure 60 when making a turn, the acceleration force due to the turn will exceed the gravity force acting on th pendulum bob and cause the pendulum I3I to move so as to engage the contact I33 with either of the spaced contacts I36 to cause thesignal horn I40 to be energized and thus announce to an observing instructor the improper co-ordination of the lateral and directional controls. This signal system thus at all times forces the student when turning the trainer to apply sufficient lateral control to maintain the pendulum I3I in substantially its central position so'that the contact I33 is out of engagement with either of the contacts I34, and failure of the student to proptive resistance elements 11 and I8 by means of limit switches HI and I42 respectively, which switches are adapted to de-energizethe motor I3 whenever the nut II which actuates the shiftable cowl section 06 in Fig. 1 has traveled along the lead screw 72 to either of its limiting positions, whereby it engages either of the respective switches I4I or I42. The limit switch I 42 is of the double pole type and having a separate, switch connected by means of theconductor I43 to the positive terminal of the battery I50 and serially connected to the solenoid controlled dashpots 8! and I I 5, previously described, and thence is serially connected to an electric signal horn I 45 and to the return side of the battery I50 through a grounded'connection. When the traveling nut 1I approaches the first switch of the double pole switch I42, and corresponding to an elevation of the'line of sight across the top of the shiftable cowling section 66 of Fig. '1, amounting to approximately 16 degrees, the electric circuit through the conductor I43 is completed and the solenoid'control' valves in the dashpots 81 and I I5 are energized to release-the restraining influence of'the dashpots on the movement of the control column 85 in both the fore and aft and lateral directions and simultaneously causes the emission of a signal from th horn I45. The release of the restraining influence of the dashpots 8'! and H5 causes the same effect as the slopDycontrol present in an aircraft when the same approaches a stalled condition and the sounding of a signal from the horn I45 is a warning to the student that the simulated elevation of the nos of the aircraft is approaching a stalled position and that a spin is imminent; Ii thecontrol column 85 is not returned to the neutral position and a further elevation of the shiftable cowl section 56 occurs, the'traveling nut II will finally engage th limit switch arm of the switch I42 to de-energize the motor I3 and stop a further elevation of the shiftable cowl section. Since the present trainer is primarily concerned with instructing the student in the use of the controls of an air-, plane to maintain the same in level flight; and not in the performance of acrobatic maneuvers,

' which, of course, occur only at an advanced stage 1n the actual flight instruction on an airplane,

thesignal system, including the dashpots 81 and H5 and the signal horn I45, clearly simulate the condition of actual flight wherein the nose of the aircraft is allowed to inadvertently rise until the Wings have reached their stalling angle, a very frequent occurrence with student pilots who tend to concern themselves mainly with the use of the rudder and lateral control and forget about the longitudinal controls, and the emission of a signal from the horn I I is a clear warning to the student of the improper co-ordination of the longitudinal control with the lateral or directional control.

General operation Though the operation of the individual components of the trainer have been discussed above, a brief recapitulation of. the operation of the trainer as a whole, will now, be described. Upon entering the trainer cockpit 60, the engine I! having been previously started, the student will operate'the control stick 85 so as to place the cockpit inclosure 60 in the lateral level position and will move the control stick in a fore and aft direction such as to position the shiftable ccwling section 66 on a line with the visible horizon and the engine throttle is then opened to cause the trainer to be graduallyaccelerated, until a speed i of approximately miles per hour is reached. The student thenmust adjust the trimming bal anceof the trainer by neutralizing any forces onthe controlcolumn when the same is in the neutral position, by actuation of the control lever I22, described with'reference to Fig. 5, with the exception of the slightly nose-heavy load imposed upon 'the control stick until the engine throttle control lever I26 is moved from the closed position, and the trainer is then caused to traverse any predetermined course as previously instructed by the supervising instructor.

The student controls the directional heading of the trainer, as previously noted, by actuation of the rudder pedals 80 (Fig. 3), and duet ofthe provision of the signal system, including the inclinometer I30 andthe signal horn I (Fig. 6), the student must so position the cockpit inc1osure 60 so as to assume an angle of bank properly corelated to the existing rate of turn of the trainer that is, thesharpeflth'e turn, the

greater the angle of bank which must be applied and in case the student either over-banks or under-banks the cockpit inclosure while turning.

the signal system will announce to the observing instructor the failure to co-ordinate the lateral control with the directional control of the trainer and.s milarly, if the student allows the cockpit inclosure to be tilted unconsciously without turning the trainer, the signal horn I40 will also be sounded to indicate side slip or skidding. While the student is attempting to properly co-relate the lateral bank of the cockpitinclosure and directionally control th trainer tosteer a desired,

course; his attention must also be constantly directed to maintaining the elevation of the shiftable cowl section 56 sothat the lineof sight across the cowl section intersects with the visible with reference to 6,,and the signal horn I will emit a warning signal indicating the approach of the stalled flight condition. It isthus seen that in control of the trainer the students psychological reflexes are conditioned by the necessity of properly co-ordinating the directional andlateral control and since oneven COl'il'. paratively smooth terrain bumps" will cause an unconscious actuation of the control column in the longitudinal control direction, the student must also continually watch the level of the shiftable cowl section relative to the horizon, thus co-ordinating this control with the lateral and directional controls. 1

After learning to orientate the trainer similar to learning to spatially orientate an airplane, the student may be required to cause the trainer to traverse prescribed courses presenting obstacles which must be avoided, and this type of operation will to a. certain degree train the psychological, reflexes of the student since in addition to the control or the trainer to simulate the spatial orientation of an aircraft,,the student must exercise Judgment in evaluating situations such as presented by obstacles in the path of the trainer, to determine the necessary change in course to avoid the obstacle and thus becomesused to making the rapid mental decisions so necessaryto safely pilot an airplane.

. The above described trainer has the virtue that it may be employed at locations'such as colleges and preparatory schools where flying'fields and,

training aircraft are not available and serves 'also as a means for rapidly determining with a minimum of expense those students who show an aptitude for flying and who may then be in structed in a minimum of time on actual aircraft at a training center. y

Use of trainer for gunnery practice v Since the trainer in accordance with the present invention is provided with controls whereby both the lateral, longitudinal anddlrectional control of an airplane may be simulated, and also the trainer maybe causedto steer any desired course over the ground, the trainer adapts itself very well in instructingstudents on the ground in the use of fixed type machine guns such as provided on combat aircraft and to carry out such instruction the trainer is provided. as indicated in Figs. 1 and '7, with a gun J mounted on the shiftable cowl section 66 so as to be movable therewith. This gun may be a conventional semi-automatic rifle. re-worked in a well-known manner for full automatic operation, and employing, for example, .22. caliber ammunition. or the gun may be a low caliber type of machine gun such as used in practice by infantry troops, the particular type of gunbeing immaterial so,

long as the gun maybe caused to fire a plurality of rounds of ammunition by actuation ofthe trigger mechanism thereof, which, as seen in Fig. ,7, is connectedby means of a flexible push-pull control I5I to a 'trigger actuating lever I52 mountedon a control column 15 and similar to the machine guncontrol provided inactual combat'airplanes. In use the trainer .may be caused to traverse a tortuous course laid out on the firing range by. means of guide stakes or the like and suitable targets may be positionedat var ous points alongthe course-such that a target is in point blank range only for a brief instant before the trainer must be turned. or otherwise steered away from the same. and also the level of the target with reference to the normal level line of sight from the students eyes across the cowling section to the horizon may be so adjusted that the student is requlredto control the elevation of the gun simultaneously with the directional and lateral control of the trainer, thus simulat ing the actual firing upon a maneuverlng'enemy aircraft. 1 i T In the invention as illustrated in the drawings the shiftable cowl section rotatable about an axis substantially coincident with the students eyes is employed to simulate the angle made by the longitudinal axis of the airplane relative to the visible horizon because this structure is mechanically simple to construct and operate but it is obvious that the cockpit inclosure including its bearing supports, may be cradled in transverse bearings from the main frame so that the cockpit inclosure may be tilted in a longitudinal plane, separate electric servo motors, such as used for moving the shiftaole cowl section, being employed for causing both the lateral and longitudinal tilting of the cockpit inclosure.

Although a preferred embodiment of the invention has been illustrated and described, other modifications and alterations therein will become apparent to those skilled in the art as falling within the scope of the invention.

We claim: I

l. A power propelled vehicle for instructing students in the art of controlling an airplane including a main frame, supporting wheels for the frame, a power drive associated with at least one of the wheels for propelling the vehicle, at least one of said wheels being steerable for directionally controlling the vehicle and mounted at the rear of said frame, a platform having a seat thereon for the student occupant of the trainer and forming a cockpit inclosure, said platform being pivotally mounted on said main frame for lateral tilting with respect to the longitudinal axis of the main frame, reversible power actuated servo mechanism mounted on said vehicle and operatively connected to said platform to cause a tilting of the same in either direction about its pivotal axis, control means for said servo mechanism operative upon a, displacement thereof from the neutral position in either direction to cause operation of said servo mechanism in a corresponding direction, a set of airplane-type 'control elements mounted on said platform and including controls simulating the rudder and lateral control means of an airplane, a connection between said simulated rudder control means I and the directional control means of the trainer wherebythe student may directionally control the trainer to traverse a desired course, and an operative connection between the simulated lateral control means and the control means for said servo mechanism whereby the student may cause a lateral tilting of said platform to simulate the lateral control of an airplane.

plane and an operative connection between said I one control element and the control element for said power means.

3. The structure as claimed in clam-1 1, including a lateral inclinometer mounted within the cockpit inclosure and responsive to lateral tilting of said platform tnd to acceleration forces due to turning of the trainer, and an electric signal controlled by said inclinometer and operative to emit an aural signal whenever said platform is tilted without turning the trainer in a corresponding direction and when the said platform is not tilted the proper amount for a given rate of turn of the trainer.

4. A power propelled vehicle for instructing students in the art of controlling an airplane said vehicle including steering means, a means forming a cockpit inclosure for the student pivotally mounted on the vehicle for lateral tilting to simulate the bank of an airplane, power means for tilting said cockpit inclosure, power actuated-means associated with said cockpit inclosure and operative to simulate the change in position of the longitudinal axisof an airplane with re,- spect to the horizontal, a set of airplane type directional, lateral and longitudinal controls within said cockpit inclosure and operative upon manual actuation thereof respectively to actuate the vehicle steering means, control the lateral tilting of said cockpit inclosure and to control said power actuated means to simulate achange in the position of the longitudinal axis of saidairplane relative to the visible horizon, actuation of the lateral and longitudinal controls in either direction from a neutral position causing a corresponding control effect in a corresponding direction only at a rate proportional to the magnitude of the displacement of the lateral and longitudinal controls respectively. 7

5. The structure as claimed in claim 4, including a lateral inclinometer and a signal means controlled thereby, said inclinometer being responsive to lateral tilting of the cockpit inclosure and centrifugal force due to turning of the trainer, movement of the sensitive element of the inclinometer in either direction from a neutral position causing said signal means to give a Warning signal.

6. The structure as claimed in claim 4, includ ing a signal means operative in response to movement of said power actuated means beyond a pre-.

determined point from a neutral position to give a Warning signal to the trainer occupant.

7. The structure as claimed in claim 4, including a first signal system responsive to lateral tilt-- ing of the cockpit inclosure and to centrifugal force caused by turning of the vehicle to give a warning signal indicating improper operation of the lateral control of the trainer and a second signal system operative in response to the movement of the power actuated means for simulating a change in the angle of the longitudinal axis of an airplane relative to the horizon a predetermined amount from a neutral position.

8. In an aviation ground training device of the character including a means forming a cockpit inclosure for the-student being instructed. power actuated means for causing said cockpit inclosure to simulate the banking or lateral tilting of an airplane, power actuatedmeans for causing said cockpit inclosure to simulate the changing attitude of the longitudinal-axis of an airplane with respect to the horizontal, an airplane-type control column mounted within said cockpit inclosure and movable to simulate the lateral and longitudinal' control movements of an airplane control, an operative connection between each of said power actuated means and said control. column whereby each of said means is controlled respectively by the lateral and longitudinal movement of said control column, damping means as v sociated with said control column effective to cause a resisting force on said column proportional to the rate of deflection thereof either lat orally or longitudinally from a neutral position,

. 3,815, 81., and means for rendering saiddampinsmcans-im;

by the said means for renderingthe damping means ineffective to give a warning signal concurrent with the release of the restraining force or said damping means on the control column.

10. In an aviation ground trainer of the char- Q "d s motor control element.

14. The structure as claimed in claim' 13, in

I which there is provided an electric solenoid conacter described having a control column movable in a manner equivalent to the lateraland longitudinal control movement ot an airplane control,

. means yieldingly resisting the movement of said control means in direction oi! control movement proportionalto the rate of movement of said control column irom a neutral position and means for rendering said yielding means inefiective upon a movement of said control column in one direction.

11. The structure as'claimed in claim 10, in

which there is provided a signal means operatively controlled by the said means for rendering the yielding means ineifective and operable to give a signalupon the release of the restraining forces opposing movement of the control column.

12. A power propelled vehicle iforv use in training students in the art of controlling an airplane including at least one steerable wheel for directionally controlling the vehicle, engine driven propelling means for the vehicle, means forming a cockpit inclosure for the student. receiving mounted for tilting about an axis parallel with the longitudinal axis of the vehicle, a power take- 08 from said engine driven propelling means, reversible servo mechanism actuated from said power take-oil and including a control element I from a level position ineither direction dependent upon the direction or operation of j said servo mechanism, and an airplane-type control column mounted in said cockpit inclosure and operatively connected to said servo mechanism control ele- 1 ment to actuate the same;

131A power propelled vehicle for use in trainingstudents in the ante! controlling an airplane. including means actuated by the stude'nt for di- 1 'rectlonally controllingthevehiclameans forming acockpit' inclosure iorjthefstudentoccupant of I i y the vehicle means 'i'orming a front cowl :section sci-saidcockpitinclosure and. shiitable above and below neutralf'positlon'which intersects the i I line of sight from the'gstudents eyesto-the visible hori'zcnfto simulate theflvarious-at'titudesof the I longitudinaljaids o umairplanewith respect to,

the horizontal, a power-actuated reversible servoa motor having a control element shiitable in either i 1 direction from a naitralgwiiicnto causeoperation of said"servomotorfj-.in i t he iforward or reversegdirection respectively at 'arate proportional to the deflection of said control element-from the neutral position, an operative connection between trolled, dashpot connected to said airplane-type control means to normally impose a resisting force to the movement thereof proportional to the rate at which it is deflected-in either direction fron the neutral'po'sition, and said solenoid control being adapted to be energized to release the restraint imposed upon said control means by the dashpot upon a movement of said shiftable cowl section beyond a predetermined point in one direction ofthe movement thereof from the neutral position; I I

15. The structure as claimed in claim 13, in which there is provided an electric solenoid controlled dashpot connected to said airplane-type shiitable in either direction from a neutral posicontrol means to normally impose a resisting force to the movement thereof proportional to the rate of movement oi said control means, an electric signal means electrically connected in series withthe solenoid of said dashpot, and means re- .sponsive to a movement of said shiftable cowl I section beyond a predetermined point in one direction irom the neutral position to cause said r si almea dsaid an t training, said cockpit inclosure being pivotally us an d 8 p0 solenoid to be come'ener'gized, whereby said signal means gives the movement of thesaid control means.

116.-The structure as claimed in claim 13, in-

cluding a gun mounted, on said shiftable cowl section and movable therewith, said gun being of a type such that operation of the trigger rmechanism thereof causes said gun to fire a numpower propelled steerable wheeled vehicle having means thereon forming a cockpit inclosure for the student receiving instruction, reversible power actuated means for causing said cockpit inclosure to simulate the banking'of an airplane,

' position.

' 18. The structure as claimed in claim 17, in

saidservo-motor and thes'aidshiitable cowl sec- '76 reversible power actuated means for causing said cockpit inclosure to simulate the level flight, climbing or descending attitudes of an airplane, manually actuated airplane-type controls mounted within said cockpit inclosure and including rudder controls operatively connected to the vehicle steering means to directionally control'the same and a control column capable of lateral and longitudinal control movement in either direction from a neutral position and connectedto said power actuated means to respectively control the same to operate at a rate and in a respective direction dependent upon the displacement of said control column from its neutral which said control column has connected there with a pair 01' resilientelements each selectively operative to impose a. force on said control column when in the neutral position equivalent to the force felt on the control column of an airplane in a corresponding position due to tall or nose-heavy conditions and manual control means within said cockpit inclosure operative to cause .either of said resilient elements to. impose a de-' sired loading on said control column.

19. The structure as claimed in claim 17, in.

which said cockpit inclosure is provided with movable means adapted to control the power 

